study the impact of exoskeleton on energy consumption Opensim

[Thomas Uchida]

In this tutorial when I plot for muscle forces in assisted gait model I can see a muscle named, PlantarFlextionAssist. I assume that this extra muscle which is absent in unassisted model is the actuator which is applied to the generic model. Is this assumption true?

The "PlantarFlexAssist" component is a path actuator (https://simtk.org/api_docs/opensim/api_ ... uator.html), not a muscle. Yes, the "PlantarFlexAssist" component represents the assistive device; see the instructions for Step VI ("Explore on Your Own: Simulate Walking with an Active Device").

[hesam boroomand]

So, how Opensim can help us to simulate movement of people with some disabilities and weak muscles. I think after doing CMC and obtaining muscle excitation we must use excitation Editor and change a specific excitation which is a number between 0-1. after that, use this edited file to run Forward Dynamics and this tool can show us created faults in walking when we play model motion in GUI. Am I right?

That strategy is unlikely to generate satisfactory results. First, you would also need to define a contact model between the feet and ground to generate GRFs in your forward simulation. Second, unless you've also implemented some sort of balance controller, the model will fall because it's an unstable system; the "Dynamic Walking Challenge" example (http://simtk-confluence.stanford.edu:80 ... Id=5113821) illustrates this well.

It isn't clear what you mean by "how Opensim can help us to simulate movement of people with some disabilities and weak muscles". If you've collected data from subjects with muscle weakness, you can run through the typical pipeline using an appropriately adjusted model (e.g., with lower values for the peak isometric muscle forces). If, on the other hand, you want to predict the kinematics of a person with muscle weakness (i.e., in the absence of experimental data), then the situation is more complicated. Here's one approach:

Dorn, T.W., Wang, J.M., Hicks, J.L., Delp, S.L. Predictive simulation generates human adaptations during loaded and inclined walking. PLOS ONE 10(4), 2015. http://nmbl.stanford.edu/publications/pdf/Dorn2015.pdf

it is mentioned that : "the OpenSim software platform has an extensive library of actuators and controllers." How we can use this library in order to add External actuators (assistant torques) to the model's joints. Is it possible without using XML Marker or Scripting? is there any helpful document in this regard?

There are at least three ways of adding components to an OpenSim model:
- Modifying the XML directly. In the GUI, select "XML Browser" from the "Help" menu to get a template for the XML code. The API documentation provides descriptions of the actuators (e.g., CoordinateActuator, https://simtk.org/api_docs/opensim/api_ ... uator.html) and controllers (e.g., PrescribedController, https://simtk.org/api_docs/opensim/api_ ... oller.html) that are available.
- MATLAB/Python scripting interface. See the "Scripting" section in the Confluence documentation (http://simtk-confluence.stanford.edu:80 ... /Scripting) for details and example scripts.
- Using the C++ API. There are examples here: http://simtk-confluence.stanford.edu:80 ... I+Examples.

Dear Thomas
As i found this topic and your answer related to my question, i want to share link of my recent question. you make me happy if reply me anything helpful.
viewtopicPhpbb.php?f=91&t=13826&p=39728&start=0&view=